1 Name Service (DNS)
In most of this book, we have been using addresses to identify hosts.
While perfectly suited for processing by routers, addresses are not exactly
user friendly. It is for this reason that a unique name is also typically
assigned to each host in a network. Already in this section we have seen
application protocols like HTTP using names such as www.princeton.edu.
We now describe how a naming service can be developed to map userfriendly
names into router-friendly addresses. Name services are sometimes
called middleware because they fill a gap between applications and
the underlying network.